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UNIQUE ASPECTS OF NAVAL AIR MISSIONS

THERE ARE MANY UNIQUE ASPECTS OF NAVY AIR MISSIONS THAT LEAD TO THE DIFFERENTIATIONBETWEEN THE 0ESlGN AND PERFORMANCE OF SHIP AND SHORE-BASED NRCRAFT. WE SHALL DISCUSSTHE MAJOR UNIQUE ASPECTS FROM WHICH ESSENTIALLY ALL NAVY AIRCRAFT DESIGN REQUIREMENTS

DERIVE.

FIRST: THE FACT THAT NAVY AIRCRAFT OPERATE FRQM CARRIERS AT SEA IMPOSES A BROAD SPECTRUMOF PHYSICAL CONOITIONS, CONSTRAINTS AND REQUIREMENTS RANGING FROM THE HARSH AT_EA ENVI-

RONMENT, THE SPACE LIMITATIONS OF A CARRIER, TAKE-OFF AND LANDING REQUIREMENTS AS WELL ASA NEED FOR ENDURANCE AT LONG DISTANCES FROM THE CARRIER.

SECOND: BECAUBE THE CARRIER AND ITS AIFIWING ARE INTENDED TO BE CAPABLE OF RESPON01NG TO ABROAD RANGE OF CONTINGENCIES RANGING FROM CONFRONTATION WITH A MAJOR POWER TO PROVID-

ING PFIESENCE IN THIRD WORLD AREAS, MISSION FLEXIBILITY IS ESSENTIAL CARRIER BASED AIRCRAFTMUST HAVE MAXIMUM WEAPON CARRIAGE OPTIONS TO MEET CHANGING OR UNKNOWN THREATS, THEYMUST BE CAPABLE OF RAPID RECONFIGURATION, AND MUST HAVE MULTIPLE MIS_ONS CAPABILITY TOHANDLE ALL CONTINGENCIES ONCE AIRBORNF-

THIRD: THE EMBARKEO AIRCRAFT PROVIDES THE LONG RANGE DEFENSE OF THE BATTLE GROUPAGAINST AIR, SURFACE ANO SUBSURFACE LAUNCHED ANTISHIP MISSH.E8. ALL CAPABILITY MUST BEORGANIC TO THE BAI"rLE GROUP.

FOURTH: THE CARRIER AND ITS AIRCRAFT MUST OPERATE INDEPENDENTLY AND OUTSIDE OF NORMALSUPPLY LINES ANYWHERE ON THE GLOBE. THEREFORE SELF SUFFICIENCY IS ESSENTIAL.

I I II

p._ll

UNIQUE ASPECTS OF NAVAL AIR MISSIONSI I I Ill I

• AT SEA/SHIPBOARD OPERATIONS

• MISSION FLEXIBILITY

• SELF-DEFENSE/FLEET DEFENSE A REQUIREMENT

• SELF SUFfiCIENCY A REQUIREMENT

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36

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II I

NAVAL AIRCRAFTOPERATIONAL ENVIRONMENT

CLEARLY, THE AT-SEA ENVIRONMENT PROVIDE8 A SIGNIfiCANT DIFFERENCE IN AIR OPERATIONS FOR THE

NAVY. THE PHOTOGRAPH SHOWS A BOW WAVE ENGULFING AIRCRAFT POSITIONED ON A CARRIER DECK.

THIS CORROSIVE ENVIRONMENT REQUIRES MAJOR DIFFERENCES IN MATERIALS AND COATINGS FOR NAVY

AIRCRAFT.

J

37

SIZE & WEIGHT LIMITS

• THECATAPUt,TTAKEOFFIMPOSF..8HARDUMIT8 ONTHE OVERALLLENGTHOF THENRPLANE ANDTIlE _ HEIGHTABOVEGROUNDFORTHE FUSELAGEAND ANYOF 11'8ATTACItMENlll, SUCHA8 CENTERUNETANK8ORWEAPONS.

• THEFLIGHTDECKGEOMETRYUmT8 THEWINGSPAN(OR ROTORDIAMETER_

• THE 19.EVATOR8REQUIRETHAT HINGF..8FORFOLDINGTHE AIRCRAFTBE EMPLOYEDWITH POWERACllMTIOK

• THEHANGARDECKIMPOSESA HEIGHTLIMITTOTHEVERTICALTAIL ORTAILROTOR,iN THEFOLDEDPOSmON.

• THETAKEO_ WEIGHT,FULLYLOADED,18LIMITEDBYTHECAPACITYOFTHECATAPULT(90_00_.

• THELANOINGWEIGHT,WITHRESERVEFUELANDUNFIREDWEAPONS,18UMITED BYTHEARREBTINGGW CAPACrrY(SUO0 _).

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rI I

• CATAPULT LAUNCH

- OVERALL LENGTH (NOSE TO TAILPIPE)

• GROUND CLEARANCE HEIGHT

• FLIGHT DECK GEOMETRY

• WINGSPAN LIMrrED FOR CLEARANCE

- ROTOR DIAMETER ALSO UMiTED FOR CLEARANCE ON SMALLER SHIPS

• ELEVATORS

- FOLD WING_ TAILS, NOSE, ROTORS TO FIT (2) AIRCRAFT ON ELEVATOR

• HANGAR DECK

- HEIGHT OF TAIL, FOLDED WINGS, OR TAIL ROTOR MUST CLEAR OVERHEAD

SHIP FRAMES

• TAKEOFF & LANDING WEIGHT

.

. ENERQY AIN_RI_ON..OV_ QEAR _

38

NAVY STRUCTURES REQUIREMENTS�CONSTRAINTS

THE DEgGN OF THE STRUCTUIqE lid OftlVEN BY THE LARGE lANDING 8INK RATE8 AND THE CATAPULT ANO ARRESTED LANDING

LOADS IMPOSED ON THE AI_ BOTH STATICALLY AND IN FATIGUE. THE MAaNI_E AND LOCATION OF THE LOADS

INFLUENCE STRUCTURAL CONFIGUIIATION, LOAD DISTRIBUTION AND MATERIAL SELL_rl0N. THESE HIGHER LOADS IMPOSE

SEVERE WEIGHT PENALTIES ON CARRIER BASED AIRCRAFT COMPARED TO LAND BASED AIRCRAFT.

THE SHIPBOARD ENVIRONMENT IIdPOeES SEVERE REQUIR_ IN AIRFRAImE MATERIAL8 USAGE AND 8UPPORTAINLrrY

ISSUES. THE LOGISTIC8 CONSTRAMT8 FOR CARRIER OPERATIONS BEING MUCH IdORE SEVERE THAN FOR LAND BASED

OPERATIONS, IMPOSE UNIQUE RIEQ4JIREMENTS FOR SUPPORTABILITY OF AIRFRAMES. REPAIR MATERIALS REQUIRE LONG

SHELF LIFE AT AMBEHT TEMPERATURES. REPAIR PFIOCEDURES MUST RE COMPATIBLE WITH EQUIPMENT AND FAClUTIE8 ON-

BOARD, AND WITHIN THE CAPABILITIES OF FLEET PEFISONNEL.

DUE TO THE UMiTED SPACE AVAILABLE BOTH ON THE FLIGHT AND HANGER DECKS, AS WELL AS .FJ.EVATOFIS, NAVY AIRCRAFT

TYPICALLY INCLUDE IdECHANISM8 TO FOLD OR STOW WINGS, ROTOR BLADES AND TAILS. THE V-_., FOR EXAMPLE,

INCORPORATES MECHANISIdS TO FOLD ROTOR BLADES, TILT THE NACELLES AN0 ROTATE THE WING TO A POSITION PARALLEL

TO THE FUSELAGE.

VSTOL AIRCRAFT (SUCH AS THE AV-SB) ALSO ENCOUNTER ELEVATED TEIdPEFIATURE8 AT VARIOUS LOCATIONS ON THE

STRUCTURE DUE TO IMPINGEMENT OF HOT EXHAUST GASES FROM THE ENGINE NOZZLES. THIS HAS REQUIRED THE

APPUCATION OF SPECIAUTY MATERIALS AND HAS RESULTED IN SERVICE PFIOBLEIdS WHICH WILL BE DISCUSSED LATER.

THE MISSIONS FOR CAFIFIER BASED AIRCRAFT IMPOSE UNIQUE FLIGHT ENVELOPES, FATIGUE SPECTRA, FATIGUE LIFE

TRACKING METHOOOLOGY, DAMAGE TOLERANCE CRITERIA AND CERTIFICATION REQUIREMENTS. THESE REQUIREMENTS HAVE

LEAD TO THE EVOLUTION OF NAVY 0ESIGN PHILOSOPHY, CRITERIA, AND CERTIFICATION PROCEDURES. THIS PHILOSOPHY AND

CRITERIA ARE SPECIFICALLY USED IN ALL PROGRAMS ADDRESSING STRUCTURAL INTEGRITY ISSUES FOR NAVYA)AARINE

AIRFRAMES. "TOUGH ENVI_ REQUIRE TOUGH CRITERIA."

NAVY STRUCTURESREQUIREMENTS�CONSTRAINTS

• HIGH SINK RATES

• CATAPULT AND ARREST REQUIREMENTS

• MAINTENANCE LOGISTICS AND SUPPORT EQUIPMENT

• MAINTENANCE AND INSPECTION PROCEDURES

• FOLDING STRUCTURE

• STRUCTURAL TEMPERATURES

• DESIGN PHILOSOPHY AND CRITERIA

• TESTING AND CERTIFICATION REQUIREMENTS

• AIRCRAFT USAGE

• FATIGUE LIFE TRACKING METHODOLOGY

39

_lllml

GROUND LOA_ COMPARISONCARRIER VS. SHORE BASED

FIGURE DRAMATICALLY ILLUSTRATES THE SIGNIFICANT DESIGN LOAD REQUIREMEN1P8 FOR A TYPI-

CAL NAVY CARRIER BAllED AIRCRAFT COMPARED TO A SHORE BASED AIRCRAFT.

r

GROUND LOADS COMPARISON (_CARRIER VS. SHORE BASEDI I I

DRAG BRACE:

CARRIER - 435,000 LBSSHORE - 0

MAX LANDING:

CARRIER - 236_00 LB$

SHORE. 74,000 LB8

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41

NAVY COMPOSITE STRUCTURES EXPERIENCE

THE NAVY HA8 20 YEAR8 OF COMPOSITE EXPERIENCE. THE NAVY INITIATED THE USE OF ADVANCED

COMPOITE8 IN PROIXJCT1ON AIRCRAFT DURING THE EARLY 70'8 WITH THE LIE OF 1:-14 8TABILATOR8WITH BORO41MEI_mT mGIM8 OVER A FULL DEPTH HONEYCOMB CORE. DURING DEVELOPMENT OF

8UIFSEQ4JENT AIRCRAFT, THE USE OF COMI_ INCREASED. TIlE F-18 DESIGN INCORPORATEDGRAPHITE/EPOXY WING SKIN8 AND HORIZONTAL AND VERTICAL TAILS. THIS WAS A VERY CONSERVATIVE

USE OF COMPOgTE8. THE PROGRAM 8CitEDULE ALSO ALLOWED TIME FOR RBDEBIGN 8HOULD A MAJORTEST FAILURE OCCUR IN THE _ _ THE AV-88 DESIGN WAll _ _E IN THE USEOF COMPOSITES AND THE FIRST ALL COMPOSITE WING, FORWARD FUSEIJIIGE AND HORIZONTAL

STAINLATOIR WERE INCORPORATED FOR _ tN THIS NRCRAFT, TttE _ OF COMPOSITESPERMITTED INCORPORATION OF A 15% _ I_ WING WITH A MOOERATE WEIGHTSAVING8 OVER THE _ METAL AV41A WING. RECENTLY, TIlE A-e _ EFFOffT RESULTED INEXTENSNE USE OF GRAPI'IITE FOR THE WING 8KIN8 AND IdUCH OF THE 8UBelRUCI'U_'qE TO MEETINCRF.JU_ED FATIGUE AND LOAD REQUIREMENT8 AT NO INCREASE IN WEIGHT. AGAIN BECAUSE OF

WEIGHT CRITICALITY IN A VSTOL APPLICATION, THE V-22 AIRCRAFT INCORPORATES A NEARLY ALL COM-POSITE WING AND FUSELAGE STRUCTURE.

rI

NAVY COMPOSITESTRUCTURES EXPERIENCE

I IIII • H II

EVOLUTIONARY EXPANSION OF PRODUCTION APPLICATIONS

F-14 1% 1970

10% 1978

26% 1982

38% 1988

50% 1990's

F/A-18

AV-8B

A-6 WING

V-22

49.

F-18 COMPOSITE STRUCTURE

GRAPHITE/EPOXY USED PRIMARILY ON WING AND STABILIZER SKINS AND CENTER FUSELAGE DORSAL

FAIRING, SPEED BRAKE AND WING FLAPS.

II

43

A V-8B COMPOSITE STRUCTURE

GRAFtUTE/EPOXY USED IN WING, FUM_II, GE, AND TAIL 8TRUCllJRE_ WIN8 IS MULl1411NEWAVE 8PAR/RtBSUBS'rRucll,_E CONSTnUCTION. GRAPHITE/EPOXY IS AlSO UMD IN THiS HORIZONTAL STABILIZER ANDRUDDER. GRAPHITE/BMI APPUCATION8 INCLUDE STRAKE8 AND LOWER 8KIN OF THE MAIN FLAP4.

44

A V-SB HORIZONTAL STABILIZER

SKINS ARE GRAPHITE/EPOXY TAPE. SUBSTRUCTURE IS GRAPHITE/EPOXY CLOTH. SUBSTRUCTURE IS

INTEGRAL WITH LOWER SKIN.

t.

i

45

A.6 WING

GRAPItlTE/F.POXY IS USED IN THE PLANKED 8KINS AND INTERMEDIATE SPARS AND RIBS ALL BOUNDARY,

CLOSE-OUT SUTURE IS TITANIUli¢

46

I II I .[

V-22 COMPOSITE STRUCTURE

GRAPHITE/EPOXY IS USED FOR THE WING AND FUSELAGE. THE WING IS PLANKED SKIN/MULTI-RIB DESIGN.

ALL SPARS AND RIBS, WITH THE EXCEPTION OF THE TWO OUTBOARD RIBS, ARE GRAPHITE/EPOXY.

FUSELAGE STRUCTURE 18 STIFFENED SKIN. THE ROTOR GRIPS ARE FILAMENT WOUND GRAPHITE/EPOXY

AND THE YOKE AND ROTOR BLAOES ARE WOUND FIBERGLASS.

I i

4,7

c_srre USA_ USAPPROACHINGSTABILITY

A_CHING STABILITYI Ill

%

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0

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30

F-14 1.0%F-18 10%AV418 2ira

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48

SH-60B

COMPOSITES ARE USED IN THE FOLLOWING COMPONENTS OF THE SH-60B

MAIN ROTOR BLADES

TAIL ROTOR BLADES

CABIN FLOOR PANELS

ENGINE COWUNG/WORK PLATFORM

RAOOME, TRANSMISSION COWLING

TAIL ROTOR DRIVE SHAFT COVER

THE LEADING AND TRAIUNG EOGES OF THE HORIZONTAL STABILIZER ARE ALL OF COMPOSITE

CONSTRUCTION.

FATIGUE RESISTANCE AND CORROSION RESISTANCE WERE THE MAIN REASONS FOR CHOOSING

COMPOSITES, ESPECIALLY IN THE ROTOR BLAOES.

I I II I I I II I II II I I

II I I I II I

49

I fill IN[

OTHER VEHICLE APPLICATIONS

COMPOSITE8 ARE USED IN VARIOUS APPUCATION8 ON OTHER HELICOPTER 8TRUCTUflE. BELOW 18 A LIST

OF VARIOUS HEUCOPTERS TOGETHER WITH C_ USAGE AND REASONS FOR 11"8UBE.

MAIN ROTOR BLADEB - THE MAJORITY OF COMPO_TE BLADE8 IN USE TODAY ARE MADE WITH

FIBERGLAU SKIN8 OVER A NOMEX HONEYCOMB CONE.

FLOOR PANELS - FIBERGLASS SKINS OVER A NOMEX HONEYCOMB CORE 8UCH AS IN THE BH-

eOB.

IN THE MH-53E, THE COCKPIT, ENGINE ANO TRANSMISSION COWLINGS, WORK PLATFORI_

PORTION OF VERTICAL STABILIZER, AND SPONBON8 ARE KEVLAR WITH A REINFORCING LAYEROF GRAPIETE.

MI-1.53ESTUB WINGS - KEVLAR SKIN8 WITH A REINFORCING PLY OF GRAPHITE.

CH-46 8TUB WING8 - GRAPHITE/EPOXY SKINS WITH NOMEX HONEYCOMB CORE. COMPOSITEDESIGN/CONSTRUCTION ALLOWS FOR MORE FUEL VOLUME THAN TRADITIONAL METAL

8KINISTIFFENEFI.

COMPOBrrE MATERIAL8 HAVE BEEN 8ELECTWELY APPUED IN OTHER _ OF FUGHT VENICLE8

CURRENTLY UNDER DEVELOFtSLq_. THESE VEmCLES mCLUOE SMART WEAPONS (NW_ RPV_ (P_HEEn)AND AIR LA_ MI881LES. FOR APPLICATION8 TO 8YETEM8 OF THIS NATURE, EMPHASIS 18 PLACEDUPON LOW MANUFACTUNNG COSTS IN CONJUNCTmN wrm _GH PRODUCl_N RATES. THIS LEAD8 TO

BEllE-AUTOMATED PROCESSES SUCH AS fiLAMENT WINOING, REraN TRAINtFER MOLDING ANDCOIdPREBSiON MOLDING. FAIIGUE 18 NOT AN 18SUE IN THESE APPLICATION8 BECAUSE OF THE VEHICLE'SSHORT SERVICE LIFE.

rn I I I II I II I

OTHER VEHICLE APPLICATIONSOF COMPOSITESI

UA S

SH-60B AIWS

MH-53E RPV'S

AH-1 AIR LAUNCHED MISSILES

CH-46

1 L IIULIi

50

pr_ -q

MAJOR BENEFITS TO NAVY

THII NAVY RECOONIRD IIARLY THAT COMPOIITEll OFFIIRED MAJOR IENIFI'I'I TO NAVY/MARINII AIR.

CRAFt OPIIRATING IN 11'11l ItttlqlOMID EIWIRONMENT, THE RIIQUIRIMIKr TO DEVELOP A vrl'oLAIRORAIrr IN THE EARLY ?O'BREtNIIOIqCED THE NEED 1'0 Ullll COMPOErrllll TO REDUCE THE ll'rlqUCTURALWEIGHT FRACTIONll,

IBRVlCE LIFE REQUIREMINlll HAVE lllllN INORIIAlllNG OVER THE YllARll. EARLIER AIRCRAIrr HAD

DESIGN LIVlll OF 4000 HOURll; THE F,11 II DIIIONID TO IO00 UHT HOURI. THE A,4 COMPOIrrE WINGHAll A DIllON IJFll OF MOO FLIGHT HOURI AND THE V-_I Ill DEIIGNED 1'0 I0,000 HOURlk THIIliEINCRIIAIID REQUIRllMB¢IT HAVE PROVIDIID ADDmONAL INClllCrlVEll FOR THE UllE OF ADVANCED COM.pollri'lI WHICH ARE EINHIN'rlALLY INllllNlllTIVl 1'0 FATIGUE.

THII NAVY'G OPERATING ENVIRONMENT MAKU CORROIION CONTROL A HIGH COBT MAINTIINANCII ITEM.THE FACT THAT COMPOBITE8 DO NOT CORRODE Ill THUII OF EXTREME IMPORTANCII TO THE NAVY.

TI-IEIIE BIINEFITII TAKEN TOGETHER RE8ULT IN INCREASED PERFORMANCE, LOWER LIFE CYCLE COST8,AND INCREAIIED MIBIIlON AVAILABILITY.

tm

(_ MAJOR BENEFITS TO NAVY (_I

• REDUCED WEIGHT

• INCREASED FATIGUE LIFE

• CORROSION RESISTANCE

INCREASED PERFORMANCE

AND AVAILABILITY

51

THIS PAGE INTENTIONALLY BLANK

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AIRCRAFT WEIGHT SAVINGS

CHART 8HOW8 WEIGHT SAVING8 FOR VARIOUS AIRCRAFT WHICH INCORPORATE ADVANCED COM.posrrlE MATERtAL8. THE PERCENT COMPOSITES BY WEIGHT HAS INCREASED OVER THE YEARS A8

CONFIDENCE IN THEIR USE WAS OIITAINED.

CURRENTLY FLYING NAVY AIRCRAFT HAVE SHOWN 81GNiFICANT WEIGHT 8AVINGB THROUGH THE USE OF

ADVANCED COMPOaTE8, THE MOST DRAMATIC OF WHICH IS THE I/-22 WHICH SAVED 15% (ALMOST 2000POUNDS) UmNG mMAmLY GRAPtITE EPOXY.

IT 18 INTERE811NG TO NOTE THAT AS PART OF THE TRADE STUDIES LEADING TO 1TI _ V_ _, ACOMPARBON WAS BADE BETWEEN THE GRAPttlTE/F.POXY WING TORQUE BOX AND AN EGUlNALENT ALU.

TORQUE BOX DESIGNED TO THE SAME cR_rERUL IT WAS FOUND THAT THE WEIGHT IIAVlNG8

ACtUEVED _H THE USE OF COMPOSrrE8 WAS 591 POUNDS OR 28% OF THE WEIGHT OF THE METALTORQUE BOX. THE SAME MATERIAl.8 USED IN THE WING ARE AlSO USED FOR THE I:USELAGE ANDlmPENNAGE OF THE V-22.

THE WEIGHT SAVING8 SHOWN FOR THE A.4 WING REQUIRES SOME EXPLANATION.

THE A4 DEWGN REWING REQUIREMENT8 WERE:

. OIlO0FUGHT HOUFI8 IN81-r.AD OF IKX)OFLIGHT HOUR8

. :i0% INCREASm IN LOA06 OVER THE OflI(MNAL DEglGNI, OADI

11,lESE _ WERE TO BE ACCOMPANIEO BY NO _ IN WUm _ WEIGHT. THE_0

POUIB IIbIGHT 8AImq_8 81t0_H 18 TI_ WI_IHT SAVED OVER A MIETALDIWQN _ OF T_ _SAME LOADe AS THE _.

I

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AIRCRAFT WEIGHT SAVINGSI i

AIRCRAFT AIRFRAME % COMPOSITES % WBGHT LBS WEIGHT

T/M/8 WEIGHT (BY WBGHT) SAVED SAVED

F-18 11:110 m

AV4B

A4 ¢Wm)

V-Z!¢_m14nOTOR)

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55

METAL FATIGUE PROBLEMS

Tmmm TV_ ___.m-r_._U u T_ FA_.tTIT mira _ umncz, m 'me_ _ ALUm ia_ mm HmH LOADSAReI_ AT mO _ L_m U ATTa_eerm, _ __ OUmNO11 _.8CAI.E FAI_IUE 11M'. TH| _ lililTIATEDAT HIGHIn_lma _ M TO LOCAL RAOtlIn'RE88_Tmlm. LqXlmWEnE DEVlLOPUD_IOTHE_AT_UETESTM_GfU_WASCONmtUED. iNre)tiE InSTANtS, THBE FATIGUEImom.Eim Juu[NOT_ UHT_ A NUlUER OF _JnC_4FT HAVEALREADY IBm OEUVEMO TO THE FLEET, AND REWORK,WHICH CAN 8E Bml_=LY COSTLY FORINTERNALmUCTURE, 18NECE98ARYFORALLNRCRAFTOFTHI8TYPE.

ri ii

(_ METAL FATIGUE PROBLEMS (_

./..'"

//

FATIGUE GNACK --_ /

I I III I ( I I I IIIIIII I IIIII I I I II I I II I I IIII I

PHOTOGRAPH OF F-18 COMPOSITE BULKHEAD

THE NAVAL NR DEVELOPMENT CENTER AND MCDONNELL NFICRAFT COMPANY HAVE DESIGNED, FABRI-

CATED AND TESTED A HIGHLY LOADED WING ATTACHMENT BULKIf.AD WHICH DEMONSTRATE8 THE

WEIGHT AND FATIGUE ADVANTAGES OF AN ALL COMPOSITE MAJOR LOAD CARRYING COMPONENT. THE

BULKHEAD WAR DESIGNED TO MEET THE FORM AND FUNCTIONAL REQUIREMENTS OF THE F.18 FUSELAGE

STATION 453 BULKHEAD. TWO ARTICLES WERE FABRICATED: THE FIRST BEING A MANUFACTURING

DEMONSTRATION ARTICLE, ANO THE SECOND INCORPORATING FABRICATION L_ LEARNED, A

STRUCTURAL TEST AFITICLE.

FABRICATION OF THE SECOND FULL 8CALE ARTICLE, USING II_'/N81.TA GRAPtlITE/EPOXY PREPflEG, AND

TESTING OF THE CARRY-THROUGH BEAM PORTION VERIFIED THE PROOUCIBILITY, STRENGTH AND DURA-

BILITY OF THE DESIGN THEREBY PRESENTING THE OPPORTUNITY FOR USE ON AIRCRAFT UPGRADES AND

NEW AIRCRAFT. FOLLOWING TWO LIFETIMES; OF ENHANCED, TO ACCOUNT FOR COMPOSITE SCATTER, F-18

WING FATIGUE LOADS THE BULKHEAD WAS SUCCESSFULLY LOADED TO FAILURE WHICH OCCURRED AT

186% DESIGN LIMIT LOAD. A 15% WEIGHT SAVING8 WAS ACHIEVED AND, MORE IMPORTANTLY, THE

FATIGUE PROBLEM8 THAT NORMALLY PLAGUE METAL BULKHEAD ARE VIRTUALLY ELIMINATED.

I I III I I I I I I I IIIIII I II _1 I I [I I Ill _da

57

MAJOR._EFITS TO NAVYI II I

• REDUCED WBGHT

• INCR_ FATIGUE LIFE

I INCREASED PERFORMANCE tAND AVAILABILITY

I I II

1_ ..... i_ _ (_ENVI_AL__-__:__..... DEGRA__II I

. CORROSK)NmASmN_CANTmINTaNANCSussuu_

• CORROSION ACCOUNTS UP TO 15% OF THE MAINTENANCE MAN-HOUR8

• COSTS RELATED TO CORROSION, 900 MILLION DOLLARS FOR NAVAL

AIRCRAFT

• comosrrs mTSmWLJREDUCE__ HOURS

I .1111I[ lllll I

UNSCHEDULED MAINTENANCE EXPENDED ON CORROSION

CORROSION MAINTENANCE MANHOUR8 REFLECT A GENERAL DECREASING TREND DESPITE AN AGINGFLEET DUE TO:

• IMPROVED CORROSIONCONTROL PROOUCTS_ROCEDURE8

- UTILIZATION OF IMPROVED MATERIALS SERVING AS BARRIERS; I.E. COATING8

- IMPROVED ME1TIODSOF ASSEMBLY

- PROPER DESIGN CHOICE8 OF METALUC MATEFIIAL8

- IMPROVED SURFACE TREATMENT8

• USE OF POLYMERIC COMPOSITE8

r _

UNSCHEDULED MAINTENANCE EXPENDED (_ON CORROSIONI I I]i i ii ii

TOTAL MAINTENANCE CORROSION MAINTENANCE % CORROSIONAJRCRAFT DMMH/YR THOUSANDS DMMH/YR THOUSANDS MAINTENANCE

A.4

E.2

I.,1

1=-14

F-18

US1

$,143

2,401

418

337

99

3O3

232

11

is

7.7

9.8

9.7

2.6

m o_vyoqw_Jo_ md W Jw_11_MHk MMMemnoem

59

I

DESIGN DRIVERS ARE INCREASING

F.k_Y k,mUCATmNSOF _ _ CONCeRNeDPWf,_LV wrm nF.OUcmarmumun_WEIGHT. THIS WAll THE MAJOR DRIVER FOR THE USE OF _ IN THE 1=-14, 1=-18 AND AV-IB. IN

111ESE APPIJCATION8 18-20% WEIGHT IIA_Itl WERE ACHIEVED.

ntO.NT Amcnk-r mooma_ (v4: & _ wm_) HAW moLuono _ _Uda_ _0 m_vw_m_Tv mmwam.m_T_ oAmmu _ ___ATtOw .mumvo_¢,_ae .Aw mm ..CLUmm TO¢O,FO,m wrr. T_.R_W _ OF._r .eau, ma .oun_,,mPmCT_U. THUS.Omnv,cm ups _ uusrme Mn" w,_ l_muooT OnvBm non-v,m_DAMA¢I!Iq_IIILF. III_ClI.ID IUItVtVABtlJTYnEQUINIMINll FOIPlTHE81AIIPlClI_'TWERIAImlgt.I _BY A 2mlM HEI PflOJECTllLL

IN THE FUTURE, IT 18 ANTICIPATED THAT IN ADDmON TO CURRENT DRIVER8, LOW QOSEIWABH.rlrY,

QUALITY, COST AND SUPPORTABILITY WII.L H IMPORTANT. IN FACT, IN THE CURRENT CUMAlt OF

BUDGET REDUCTIONS, COOT COI¢81DEFIAllON8 MAY BE OF EQUAL IMPORTANCE TO WEIGHT.

h_I I I I I II II

ip-

II III I ITlll]ll I F II I I

PAST(1970'S) (1980'S) (1990'$)

F-14 V-22 INTERIM F/AF-18 A-6 AXAV-8B ?

iOAMAaETOL.]ISURVIVABILITY

WBOHTDAMAGE TOL.SURVIVABILITYLOW OBSERV.QUALITYCOSTSUPPORTABILITY

mCnSAsa aDEMANDS

i _ _ nun ] .... Ilia

6O

IIII I

II

I . II II I IIIIII III I III

I I I

61

r_ NAVY ASSESSMENT OFCURRENT COMPOSITE STRUCTURES_-_ATIOI_ GEI_Y |

_mm_momE smt_rumss_ HAVEm.N FAVOR_LL iNm_ NOm330 OI IFA3'[_ F,IW.U_ HAVE _O. CURRENT FLIGHT TES_NG OF THi V-22 HAS NOTI_ STRUCTURAL PROBLEm; HOWEVER, THIS TESTING 18 STILL IN 11'8EARLY STAGES ANDTHE _ I_E HA8 NOT AS YET BEEN EXTENDED TO INCLUOE ALL CRITICAL DESIGN

_ ANO PROOUCllON COSTS HmH

I!ECAUM[ OF THE _ EXPERIENCE WITH _ STRUCTURE8 WITHIN THE INDUETIW,TO _ AN EXTEIIVE OEVELOPMI_"r PROGRAM PRIOR TO FULL SCALE TESllNG 18

_ COI_t:IHED AteCESmTY. 11_ COETS AmE NI_t mrr _IE Exlq_rED TO M PART OF ,mYIqmGRMI IN THE FORESEEABLE FUTURF_ BASIC MATERIAL CO6111 ARE HIGH AND CURRENT

lUNUF_'llJRING ANT) INSPECllON PlqOCEDURES ARE EXTREMELY LABOR INTEN01VEIN HIGH co_rL THESE C06T8 MUST BE REDUCEO TO INSURE CONTINUED EXTENSIVE USE

OF com_Mnm m FUTURE _C SYSTEM_

!!__ ..__I_NqUFACTURING MLrrHODS USED TO FABRICATE COMPO61TE PART8 HAVE PROGRESSED LITTLEIN THEPAI;I" m YEAR_

MANUFACTURING DICREPANCIE$ SUCH AS OELAMINATION8 AND INCLUSION8 NEM_N A PROBLEM INBO'lrl,I PART FAB18CATION AND FINAL AB6EI_LY.

NEW MA'NERIAL raM8 ARE NEEDED W111,1IMPROVED DAMAGE TOLERAI_K,_EAND STRENGTH ATCNTICAL IU,MflOIOIENT8 TO BETTER MEET INCREASIHG DEMANDS OF FUTUflE WEAPON8 8YgTEMG.

NO MAJOR _ AI"I'fllBUTED TO _ USE OF _ HAVE BEEN ENCOUNTERED IN"ALlt.lOUGH DAMAGE TOLERANCE 18 AN ON-GOING CONCERN, EXPENENC_ TO DATE HAVE

IItOWN rr TOI_E MI_IE OFA PROBLEM IN THE FACTORY THAN IN OPERATIONAL 815WICE.

ALTHOUGH _ AND EQUIPMENT ABOARD THE CARRIER ARE UMITED, COMPOSITES HAVE BEEN_IOWN TO BE SUPPORTABLE IN TH18 ENVIRONMENT.

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. • PERFORMANCE EXPECTATIONS GENERALLY MET

• DEVELOPMENT AND PROOUCTION COSTS HIGH

• MANUFACTURING TECHNOLOGY LAGGING

• MANUFACTURING QUALITY CRITICAL ISSUE

• BE1TER MATERIALS NEEDED

• SERVICE EXPERIENCE FAVORABLE

• SUPPORTABLE IN CARRIER ENVIRONMENT

[I li I I

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PRODUCTION EXPERIENCETHE NAVY PERIOOICALLY CONDUCTS QUALITY AUCIT8 OF ON-GOING PRODUCTION CONTRACTS. THESE

AUDITS, KNOWN AS PRODUCT ORIENTED SURVEYS (PO$) HAVE UNCOVEREO A NUMBER OF I_tUE8RELATED TO MANUFACTURING AND QUALITY ASSURANCE OF COMPOSITE 8TRUCTUREIi. MAJOR ISSUE8

INCLUDE:FLOWDOWN - EARLY IN THE DEVELOPMENT PHASE, ENGtNF.ERING IS INTIMATELY INVOLVED

IN THE FABRICATION OF PARTS. AS PRODUCTION 8TAR'rs, ENGINEERING'8 INVOLVEMENT _ TO

DECREASE. ONCE PRODUCTION IS UNDERWAY, ENGINEERING SUPPORT iS PRACTICALLY NON.EXISTENT.

THIS RESULTll, IN 80ME CARES, IN CHANGES BEING MADE WITHOUT CONS'AJt.TING WITH DESIGN AND

STRE88 ENGINEERS WHICH MAY EFFECT THE STRUCTURAL INTEGRITY OF THE PART.

- IN MANY CASES IT HAS BEEN OBVIOUS THAT TRAINING IN THE PROPER HANDLING ANDFABRICATION OF COMPOSITE PARTS IS INADEQUATE. THIS RESULTS IN REDUCED OR UNACCEPTABLE

QUAUTY PARTS.

proem- VERIFICATION & CONTROL - IN MANY INSTANCES IT IS OBSERVED THAT THE CONTRACTOR 18-NOT ADEQUATELY INCLUDING PROCESS VERIFICATION PANELS TO ACCOMPANY MAJOR PAR1"8 DURING

THE INTENT OF THESE TRAVELER PANELS iS TO PERFORM DESTRUCTIVE TESTING TO

VERILY MA1T=RIAL QUAUTY AND PROCESSING.

FQi:llqlll_q MATERIAL INCLUSIONS AND DETECTION - A MAJOR PROBLEM DURING FABRICATION OFCOMPOSITE PARTS REMAINS THE INCLUSION OF FOREIGN MATERIALS WITHIN THE LAMINATE. THIS

PROBLEM EXIST8 AT VIRTUALLY ALL FABRICATION FACII.JTIES AND RESULTli IN SCRAPPAGE OF MANY

PANTS. ALTHOUGH ALL CONTRACTOR8 ARE AWARE OF THIS PROBLEM, AND EFFORT8 ARE UNDERTAKEN

TO ELIMINATE IT, IT 8TILL EXISTE. FURTHER, MANY OF THESE MATERIALS CANNOT BE DETECTED WITHOUT

EXTENSIVE NON-DESTRUCTIVE INSPECTIONS.

MACHINING • DRILLING - IN MANY INSTANCES MACHINING AND DRILUNG WERE NOT PERFORMED IN

ACCORDANCE WITH COMPANY ISSUED SPECIFICATIONS RESULTING IN FIBER BREAKOUT ANO

DELAMINATIONS.

FIT-UP & ASSEMBLY - MAJOR FIT-UP PROBLEMS BETWEEN SKINS AND SUBSTRUCTURE REMAIN A CRITICAL

PROBLEM. EXTENSIVE USES OF UQUID SHIM ADD COSTS AND WEIGHT TO THE PROOUCT. FAILURE TO

PROPERLY SI'IIM RESULTS IN DELAMIHATIONS OCCURRING DURING FINAL ASSEMBLY.

I

MAJOR CONCERNS

• ENGINEERING FLOWDOWN

II I II

• TRAINING

• PROCESS VERIFICATION AND CONTROL

• FOREIGN MATERIAL INCLUSIONS AND DETECTION

• MACHINING AND DRILUNG

• FIT-UP

• ASSEMBLY

4 ,,"

I I I

MANUFACTURING

DEVELOPMENT OF IMPROVED MANUFACTURING _DURE8 HA8 ADVANCED VERY SLOWLY. BASI-CALLY, THE SAME TECHNIQUE8 IJSED TO FABRICATE THE AV-SB WING ARE 8TILL BEING USED.

IT IS TIME THAT MAJOR EFFORTB BE UNDERTAKEN TO REDUCE COST8 AND AT THE SAME TIME IMPROVEPART QUALITY. AUTOMATION 18_11tEOBVIOUS 80LUTION TO THIS PROBLE_ 80ME METItO08 CURRENTLYBEING EVALUATED INCLUDE TAPE LAYING MACHINE_ FIBER PLACEMENT TECHNIQUES, WOVEN PRE-FORM8 ANG RESIN TRANSFER MOLOING.

NDI _ VARY GREATLY THROUGHOUT THE INDUSTRY. CURRENTLY NIX OF ALL PRIMARY COMPOS-ITE PARTg 18 A NAVY REQUIREMENT. CONSISTENT NDi TECHNIQUES MITBT BE ESTARLBHED THROUGHOUTTHE INDUSTRY.

DUE TO INTERLAMINAR WEAKNESS OF COMPO_ ASSEMBLY METHOD8 THAT DO NOT ACCOUNT FORPOTENTIAL MISMATCHES RESULT IN OUT<)F4=LANE 8TRESSES WHICH CAUSE DELAMINATION& ASBEk_BLY METHOI)8 SHOULD ACCOUNT FOR GREAIER TOLERANCE8 WHICH USUALLY OCCUR IN A PRODUCTIONENVIRONMENT.

AND FINALLY, CURRENT TOOUNG TECHNIQUES FREQUENTLY RESULT IN INCREASED OUT-OF-TOLERANCEPARTS DURING PRODUCTION NECESSITATING FREQUENT TOOL REPLACEMENT&

r_

MANUFACTURINGI I

• COMPOSITES MANUFACTURING HAS ADVANCED VERY SLOWLY

• LARGE IMPROVEMENTS ARE NEEDED TO• REDUCE COST

IMPROVE QUALITY

• AUTOMATED LAY-UP METHODS WILL HELP

• QUALITY SYSTEMS MUST BE ESTABLISHED- INSPECTION

- NDT- QUALITY CERTIFICATION

• ASSEMBLY METHODS NEED TO RECOGNIZE INTERLAMINAR WEAKNESS OF

COMPOSITES

• TOOUNG MATERIALS AND CONCEPTS NEED IMPROVEMENT

p 65

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INCREASED EMPHASIS NEEDED ONMA NUFA CTURING QUA LITY

coMpglm_ ANEHIG_Y _ TO MAmWACnmmePlqOOmlSVMIMTm_ rr mJSTlm M(_G-NIZED THAT WHAT MAY _ TO BE A 8MALL CHANGE iNA_ VARIABLE MAY RllULT m A8mNmCANTCHNIU m iMTEmAL PI_PlmlW_ _ A imWFACltmmG PLAN_ BEOL"mI_FEOWHICHnI_OGNEES ANY UMQUE_ Im)ummlm_L TInS PLANm;Irr msAUENAB_ TO TNEa£1UN. PROmJ¢_ ENV,KNemN_Aim IliRT M _ _ FULLeCALE_'VELOPUENT,_ TO PnOoucnoN, wrm _ _ ALLOTTEDTO MAKE NL'Cme_RVCHANGUWITHOUTW TOm.L SCALETEBI'ANOFUG_ _ounma TH!!IIIUCT_ OFmATF.mALSYSTEm,QUAUTYmint M APm_ CONaDmA_TIME AND _ MUST BE ALLOCATED FOR MATERIAL VERIFICATION AND THE DEVELOPMENT OFMANUFACTUIlmG PftOCISS81_

DEmGH8 ARE UGUN.LY GENERATED ASBUtm¢G BU_ MANUFACTURING CAPAlmJlUm FOUNO _¢ THEOEVELOPMENT PtMSE OF 11E PflOGflAH RATHER THAN THO6E EX]811NG m THE _ _umr. ANA mmLT, C,_tU_ mLr_ THAN_.C,_Lrrv _Y m_s co.r. SC_J)ULL _ m _Mm_rv.m 11 PAST,_ HAS__lO ouma _ _ m _ TO mon_Tm¢ OUmTO_ OF_V Tn_SO _ U A_ momm_ AmnmFJ_mF_.Mca_. ounma m_Dt_,'_ON,atMUTV IqJnTHEn_ OUETO ¢o_r AND

_ RELATIVELY UTTLE _NG ATTENTION AND ADOfrlONAL USE OFUNSKILLED WORKER&

IN CIRDER TO INSURE MANUFACTURING QUALITY, A FORMAL METHODOLOGY TO CERTIFY THESE8 PRO-CE88EII Ikurr BE OIMLOPED.

r_] II

INCREASED NEEDEDMANUFA_ QUALITY

• C_ SENSITIVITY TO MANUFACTURING PROCESS VARIATIONS MUSTBE RECOGNIZED

• TIMELY MANUFACTURING DEVELOPMENT MANDATORY - MAY PRECEDE DESIGN

• DESIGN MUST BE MANUFACTURABLE IN PRODUCTION ENVIRONMENT

• INCREASED EFFORT REQUIRED FOR _ SHOULD BE RECOGNIZED INMATERIAL SELECTION, SCHEDULING, RESOURCE, ETC.

• METHODOLOGY TO FORMALLY CERTIFY THE MANUFACTURING/QUALITYPROCESSES NEEDS TO BE DEVELOPED

68

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MATERIAL IMPROVEMENTSe_

- FURTHER GAIN8 IN PERFORMANCE ARE MATERIALS UMITED

- HIGHER SPECIFIC 8TFIENGTH AND STIFFNE88

. ,BPROVED COMPRF.8_ON STRENGTH

• VARIABILITY- REDUCED BATCH TO BATCH VARIATIONS

- PRE-PREG REBIN CONTENT VARIATION8

• PROCESSABILITY

- BATCH VARIABIUTY, OUT TIME, COMPONENT COMPLEXITY CONTFIIBUTE8 TO PflOCE88 PROBLEMS

- KEY TO REPRODUCIBILITY

eCOST- COGT OF BASIC MATERIALS (FIBER, RESIN, PREPREG) MUST BE REDUCED

• 8PEClFICAllON8- STANDARD MATERIAL AND PERFORMANCE SPECIFICATION8 WILL IMPROVE REPRODUCIBILITY AND

REDUCE COST

• MATERIAL FORMS- MULTIPLE MATERIAL FORMS IN CONJUNCTION WiTH NOVEL PROCESSES OFFER POTENTIAL COST

SAVINGS- QUALIFICATION OF MULTIPLE FORMS MUST BE ADDRESSED

• TOUGHER RESINS

- DAMAGE TOLERANCE REUES ON RESIN TOUGHNE88

- IMPROVEIdENT8 TRANSLATE INTO 81'RUCTIJRAL EFFICIENCY

• ENVI_AL FIESISTANCE• NAVY HA8 AN EXTREMELY AGGRE881NE ENVI_

- MATERIAL8 MUST PERFORM UNDER EXPOSURE TO ItEAT, MOISTURF_ 80LVENTS, GALVANIC EFFECT8_J

r-

IItA TERIAL IMPROVEMENTS NEEDED

- PROPERTIES - TOUGHER RESINS

- VARIABILITY - ENVIRONMENTAL RESISTANCE

- PROCESSABILITY SPECIFICATIONS

- COST - MATERIAL FORMS

70

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71

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SERVICE EXPERIENCEIICtWIeIl_blilAI_:

• PLNi_ItRlOFllIN.IK_HONEYCOMB_

. IXtOPP_TOOCglPImTS

. YELLDWGEARIMPACT

• DELI4MItATIOImANDOISBONOS

. DROPPEO TOOI.S4MPACT OAMAGE

• EDGE CRUmING

• YELLOW GIAR IMPACT. NflCflNrr TO NflCRAFT CONTACT IN UMITED _ IPACE

• HOI.E _TION

- oul laLY TO MPEATIm mlOW¢ OFooolm ANOACCmII P_m.S• HF.AToaaMI

• AV.4ISTIqUCTIRmI_PQ_IDTOHOTNOZZLI_ (AOA,MAGIDIllRNGEIIH, IOWIMIN_IkIJCrvIIVmRAPH)

• CLOSI _ wrrH 01TlIR AIROUFT IUOMUST, UKIALLY ABOARD THE CARIqI_

• iN THE CASE QF THE AV-OB, 8OME HIEAT OAMAGI NAI OCCUflflED IECAUSE PILOll TAXi WITH THIR _ _ _

18 AGNNSI" PROCEOU_E ANO THE NOZZLE EXHAUIT OVIIqHF.ATS THE FLAPS.

• CgMFINO

- _ IY RUIBING OF MOVAIL! PAITr8 AGdlUNST AOdACENT 8TRUCTURE BECAUME oIIr OUT.OF TOLr:RANCE i

• OTIIR DAMAIE

- HAILOAMAGE- AFEWIHAVEBEENlllmOflTED,1MTI4THENRCRAJrTHAVINGIEENflIPAmEDANDPlk-lrUfqNEDTOImVl_

• II:

- 0IVlBUI.CmlEOAV-IIIHAV!IIIBABI_mO!B1tmNIlrOIIWlCl .- V-I IJMBER I CRAIIID ANO EVEN THOUGN THi OICIiON HAl BEEN M4OE TO IICRAP ITo TiI CRAIH WAI IRIRqffV.

ABLL

TOM OONI_LAN WILL PllSENT A PAPIR TUISOAY API1EINNOQN QN "NAVY COMPQITE MAINTENANCI ANO REPAIR EXPEI_

ENCr WlHICti WlU. GiVE A MORE COMPIMUINSNE SUMMARY OF IFIVICE EXPINIIK__d

I

SERVICE EXPERIENCE:I III I III III

• FEW RECURRING _I ENCOUNTERED

• PUNCTURE OF THIN-SKIN _EY(_)MB STRUCTURE

DELAMmATIONS AND DIStONDSEDGE CRUSHING

HOLE WEAR/DELAMINATION

HEAT DAMAGEC.AFnNG

• OTHER DAMAGE

- HAIL DAMAGEtaRO S1R._S

LANDING ZONE DEBRIS

CRASH DAMAGE

72

II I II IIII IIIIIII I I II

PHOTO OF PlEAT DAMAGED A V-8B STRAKE

THE GUN-PAK STRAKE SHOWN IN THE PHOTO WAS DAMAGED BY REPEATED EXPOSURE TO HEAT FROM

THE ENGINE EXHAUST NOZZLES IN THE VERTICAL TAKEOFF AND LANDING MODE. ONLY THE MOST AFT

PORTION OF THESE STRAKES HAS EXPERIENCED NEAT DAMAGE.

73

PHOTO OF HAIL DAMAGE

THE NEXT TWO PHOTO6 8HOW AN AV-IIB THAT WAS DAMAGED IN A HAIL lrrolqlkL THE NFICRAFI" WA,.qFLYING IN FQflMATION WITH AN A-4 Vfl.EL_ THEY tNADVEFITENTLY I__lNl_ A !'MA. 81"OflM. TIlE AV-BB

sumD _ o,u 'to ,ua. Luam scxz sum,Anj M _ _ Loemarrs _.

THE0U:FF.m_ES tNTHE_m @_ NTw_ _m mETAU£_ _mvs, no FUSS-Am) NOSSCO_ F.XOF.PTFon'rlm m'r,_ TIPA.': c_e_ _ T_ e.oms N.m Am)

W.m Am _rAmu_ LUmNO mSF.SAnt _.Um.U_L THeC__ mO covens mNEOUNDAMAGED.

BOTH AIRCRAFT RETURNED TO BAH IIAFELY. AFTER REPLACING THE UMIllD NUMBER OF DAMAGED

COMPONENT8, TIlE AV-BB WAS RETURNED TO SERVICE WHILE THE A-4 WAS 80 BADLY DAMAGED THAT ITWAS SCRAPPED.

I

74

PHOTO OF CRASH DAMAGED TA V-8B STRAKE

THE AIRCRAFT INVOLVED TAXIED AT NIGHT INTO A CONCRETE HIGHWAY BARRIER BEING USED TO BLOCK

A CLOSED RUNWAY. THE STRAKE IN THE PHOTO WAS SEVERELY DAMAGED, BUT ACCOROING TO

STRUCTURAL ENGINEERS FROM NADEPI CHERRY POINT, THE DAMAGE TO THE STRAKE AND FUSELAGE

ATTACHMENT WOULD HAVE BEEN MUCH WORSE IF THE 8TRAKE HAD BEEN MADE OF ALUMINUM. THE

STRAKE WAS REPAIRABLE, BUT IT WAS MORE COST EFFECTIVE IN THIS CASE TO REPLACE IT.

75

rII I II I

III II

PHOTOS OF A V-8B CRASH DAMAGE REPAIR

THE Aa_lFIAIrr INVOLVED EXPERIENCED A NOgE WHEEL STEERING MALFUNCTION AND DEPARTED THE

RUNWAY AT A HIGH PATE OF SPEED. AFTER THE PILOT EJECTED, THE AIRCRAFT CRASItED INTO A DITCH,SEVERELY DAMAGING THE NOSE SECTION AND WiNG TIP. IN THE PHOTO, A CRACK CAN BE 8F.EN THATEXTEND8 THROUGH THE CANOPY RAIL, OOWN THE 81DE OF THE COCKPIT, AND EVENTUALLY THROUGHTHEt.QNGr_ONe. NODAMAGE EX'm.NDED AFr OF THE CRACK. mNTHEOPINK)N(X'THEE_NEEMmOM

THE NAOP. AT CHERRY POINT, A ME'TAt. _ WOULD HAV! BEEN MORE EXl'EIMSNELY DAMAGEDmN(:m,THE ML=rN. STmJCTt_mS _ m.UL_ _ "mE OAMAOE PUmt4L'R _tFT._ WING _

SUFFEMD OAMAGE TO rm UPPER ANO LOWER SIGNS AND THe OUTSOAnD P_.OH m71NG Am) TiP roB.NADEP CHERRY POINT WAS ABLE TO RIPAJiR THE A1HCRAFT BY INm_ALUNG A NEW FORWAIqO FU

8EClION OBTAINED FFIOM MCAIR. REPAIRS WERE ALSO REQUIRED ON THE WING TIP. THE REPAIR BHOWNIN THE NEXT PHOTO OF THE WING 18 FROM A DIFFERENT AIRCRAFT BUT IS 81MILAR TO THE DAMAGE 8UF-FERED BY THIS AIACRAFT. THE OUTBOARD PYLON FITTING AND TIP RIB WERE REPLACED AND A NEW

OUTBOARD 8KIN WAg 8PUCED INTO THE EXISTING COVER SKIN. THE REPAIR TO THE SKIN SHOWS UP A8THE BLACK SECTION AT THE OUTBOARD END OF THE WING TIP.

I I I I I Iflll I] [ I I _ ]lI "]" I

76

77

78

SERVICE RELA TED CONCERNS

• COMPOSITE INDUCED CORROSION

- BREAKDOWN IN PROTECTIVE SCHEMES

COMPOSITES CAN INDUCE CORROSION OF METALS

GRAPHITE BASED COMPOSITES CAUSE GALVANIC CORROSION IN SOME AIRCRAFT ALLOYS

PROTECTION SCHEMES DEVELOPED WHICH REDUCE THE PROBLEM

BREAKDOWN IN PROTECTION SCHEMES RESULT IN CORROSION OF THE METAL

IMIDE BASED COMPOSITES REQUIRE STRICT ATTENTION TO GALVANIC CORROSION SINCECOMPOSITES DEGRADE AS CORROSION OCCURS

• SHELF-LIFE OF COMPOSITE MATERIALS FOR SHIPBOARD REPAIR

REFRIGERATED STORAGE ON SItiP8 EITHER DOES NOT EXIST OR CANNOT BE COUNTED ON. MOSTMATERIALS HAVE UMITED SHELF LIVES OF ABOUT 1 YEAR. REPAIR MATERIALS WITH SHELF LIVES OF ATLEAST 2 YEARS ARE NEEDED. NADC HAS DEVELOPED INNOVATIVE COMPOSITE REPAIR TECHNIQUESWHICH HAVE DEMONSTRATED THE SHELF LIFE OF MATERIALS TO OVER 18 MONTHS AT AMBIENTCONOITIONS AND ARE EXPECTED TO BE GUALIRED FOR AT LEAST 2 YEARS SHORTLY.

• LIGHTENING/F.MI PROTECTION SCHEMES INDUCE PENALTIES

TYPICAL PROTECTION SCHEMES USING FLAME SPRAY OR EXPANDEO COPPER FOIL TO PROVIDE LIGHT-ENING/EMI PROTECTION ADDS NOT ONLY TO THE WEIGHT AND COST OF THE STRUCTURE, BUT ALSOINCREASES THE SUPPORTABILITY PROBLEMS. BETTER PROTECTION SCHEMES NEED TO BE DEVEL-OPED.

• MAINTENANCE PROBLEMS ASSOCIATED WITH HONEYCOMB CONSTRUCTION

WATER INTRUSION HAS LONG BEEN A PROBLEM WITH HONEYCOMB STRUCTURES. IN METALHONEYCOMB IT CAUSES CORROSION, WHILE IN BOTH METAL AND NON-METALMC HONEYCOMB, IT ADDSWEIGHT AND COMPUCATES THE REPAIR PROCEDURES SINCE THE STRUCTURE MUST BE DRIEO BEFOREAPPLYING HEAT.

SERVICE RELATED CONCERNS

• COMPOSITE INDUCED CORROSION

BREAKDOWN IN PROTECTION SCHEMES

• SHELF-LIFE OF COMPOSITE MATERIALS FOR SHIPBOARD REPAIR

• LIGHTNING/EMI PROTECTION SCHEMES INOUCE PENALTIES

• MAINTENANCE PROBLEMS ASSOCIATED WITH HONEYCOMB CONSTRUCTION

79

THIS PAGE INTENTIONALLY BLANK

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81

• REPAIRABILITY

• METHODII iN PLACE FOIq m.NPBOARD REPAIR

DUE TO THE LIMITED _ 8PACE AVAILABLE, RF.PAIR PROOEDURE8 HAVE BEEN DEVELOPED THAT MINIMIZE THE NUMBER OF

UNiQJI[ TOQI_ EQUPMUiT Am MA_tL THE tACK OF AUTQCLAVES, OVEN8 ANO FIEFIPllERATED STORAGE HAll OFIWEN THEDEVIELOPMENT OF VAImOU8 iNNOVATIVE COMPO_rE REPAIR TECHNIQUES WHICH HAS EXTENOI_ Tiff[ SHELF _ OF MATEmMJ TO

OVER 1111dONTH8 AT AMBII_T G'_NDnlONS ANO PROOUCED ItlQH QUAUTY IqEPAIIq8.

• REPAIR OPTIQNS AVAfl.AB_

EOTH iOLllO AliO _ N!PAIq I_(_INIC_FJ EXIST TOOAY FOR TI_ IF.PAIq OF O_O_ _ _ IIONDIO IPSO-

_ HAYE ImlN _ P01q BOTH EXI'EI_AL PATCHFJ AND FLUlN4 REIPAIRIL _TIr_Jr, LEMP_ClmtEll INCLUOE WET LAYtlP,ImC-C_JlqD AND 8T_I_ID POmt

BOLTED MElliOINi ARE SIMILAR TO METAL WORKING TECHNIQUES ANO CAN UTILIZE ALUMINUM, ETEEL OR TITANIUM DEPENDING ON THEPRtS01CTI[O LOAIn AND FATIGUE REQUIREMENTS.

* _/REPAIFI TIME COMPARABLE TO METAL REPAIIFW

THE 8KILL LEVEL ANO TIME REQUIRED FOR COMPOSITE REPAIRS ARE SIMILAR TO THOSE RECHJIflED FOR METAL.

THE NEXT _ PROGRAMS AIM _ iN A LrrrLE MORE DETAIL IN THE FOLLOWING VU-GFIAPHE.

• MAJOR PROGRAM IN PROGREII OR THE V.22

THE V.n COMPOM_ REPI_Ft DEVlBLOPMENT _"RD) (PRONOUNCED VEE.CARD) PROGRAM 19 CURRENTLY ADORF.881NG THE DESlON OFREPNiai TO PREDICTED DAMAG41B414 ARF.IdB OF THE kartCRAFT.

• AlflCR_Y 8AI"rLE DAM_E REPAIR (Alll_) tml0EIq _IBENT

THE PUINPOEE OF &flDR I TO _ BAI"rLE DAMAGED AIRCRAFT TO THE EATYLE AS ,qOON A8 POMMILE 80 THAT THEY IdAY HAVE AR

EFFECT ON THE OUTOOM! Oi I THE BATTLE. WITH THiS IN MIND, DESIGN AND ANALYSIS _ _ BEING DEVELOPED THAT WILLUSE _ OOMPUIlIBI TO ANALYZE LARGE liEE DAMAGE TO COMPOgrrE WING 8TIMJCTUII.

• idETHOOS MHSOED r.oR LOW OINIERVAllLE _

LOW OllEImVAllLE _ _ ADOITIONAL REQUIREMB/T_ SPECIAL 0EEIQN AND REPAIR _IJIRES HAVE TO BE DEVEL-OPED WHICH DO NOT DEGRADE THE RC8 81GNATURE OF THE AIRCRAFT. WE HAVE ,JUST RECENTLY iNiTIATEO WORK ON L.O. REPAIRS.

r _

REPAIRABILITYIIII

METHODS IN PLACE FOR SHIPBOARD REPAIR

- REPAIR OPTIONS AVAILABLE

- SIMPLICITY/REPAIR TIME COMPARABLE TO METAL

• MAJOR PROGRAM IN PROGRESS ON V-22

• AIRCRAFT BATTLE DAMAGE REPAIR UNDER DEVELOPMENT

• METHODS NEEDED FOR LOW OBSERVABLE STRUCTURE

82

83

I I II I I I I I II

THE 1/.22 COMPOSITE REPAIR DEVELOPMENT PROGRAM

....... r . .__ .... [ .... . ............. . ........

_ _" __.:_ -:--

V,2 OPMENTIIII .......... _..:____......... ..............

a,

• t REPAIR8FORDEPOTLEVEL FUWELAGESTABIIJTY-CRrrlCALS1TIUCTUR|, :i ItlEPAIR8FORFII[LD LEVEL • 2 FilEPAiR8FORDEPOTLEVEL

• 2 REPNR8 FORVIELDLEVEL

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84

II I I I II II I I [ I I I I I I

ABDR

DEVELOP PC BASED ANALYTICAL TECHNIQUES FOR RAPID REPAIR OF COMPOSITE WING STRUCTURES

THIS COMPUTER CODE WILL PROVIDE AN ANALYTICAL TOOL TO AN AIRCRAFT BAl"I%E DAMAGE REPAIRASSESSOR OR ENGINEER TO DETERMINE THE STRUCTURAL CONDITION OF THE UNDAMAGED, DAM-

AGED, AND REPAIRED _rRUCTURE, IN LESS THAN ONE HOUR.

SIMPUFIED ANALYSIS FOR RAPID DAMAGE ASSESSMENT/REPAIRS

A PERSONAL COMPUTER BASED ANALYSIS PACKAGE TO ASSESS THE INTEGRITY OF LARGE SCALERAPID REPAIRS IS BEING DEVELOPED FOR BOTH CURRENT AND EMERGING COMPOSITE WING STRUC-

TURE8 IN THE NAVY INVENTORY.

RAPID ANALYSIS FOR FIELDED DESIGNS

A STRUCTURAL LIBRARY WILL CONTAIN DETAILED FINITE ELEMENT MODEl.8 OF THE FIA-18, AV-SB, A-6

RETROFIT, AND V-22 WINGS. THE WING MODELS CAN BE MODIFIED INTERACTIVELY TO INCORPORATELARGE SCALE DAMAGE IN SKINS AND SUBSTRUCTURE. BY USING USER-FRIENDLY AND MENU-DRIVEN

INPUTS, REPAIRS CAN BE RAPIDLY DESIGNED FOR THE DAMAGE AT HAND.

THIS ANALYSIS CODE WILL ALLOW THE DESIGN OF SUBSTRUCTURE AND SKIN REPAIRS AND TAKE INTOACCOUNT THEIR INTERACTION. THE CODE MAY BE EXPANDED TO INCLUDE OTHER COMPOSaTE STRUC-TURES SUCH AS THE FUSELAGE AND EMPENNAGE.

I II I I

rI

AIRCRAFT BATTLE DAMAGE REPAIRI " I i IIII1_11111 I I III I I ill II IIIII I I T r

• DEVELOP PC BASED ANALYTICALTECHNIQUES FOR RAPID REPAIROF COMPOSITE WING STRUCTURE

• 81MPUFIED ANALYSIS FOR RAPIDDAMAGE ASSESSMENT/REPAIR

• REPAIR ANALYSIS FOR FIELDED DESIGNS

• SKIWSUBSTRUCTURE INTERACTION

_lBI I I [ I III I I I II I i J

85

lllli iJ I | .,_

DESIGN ISSUES

TH! _ INFFERENC_ BETWEEN METAL8 AND COMP_NT_ NECE881TATEI NEW CERTIFICATIONRIEG4/mliBNTaLOUT-OF-Pt,AIE L{UWiNG AND ASSEMBLY INDUCED DELAMINATION8 ARE CRITICAL 188UE8 THAT MUST BEDEALT WITH IN DEIGN AND ANALYm8 BECAtJSE OF THE LOW INTERLAMINAR 8TltENGTH OF COIlaPCMIlm.

_ ARE BEING WORKED JOINTLY BY THE NAVY AND THE FAA ARE DISCUSSED IN MORE DETAILIN THE FOLLOWING VIEWGRAPHS.

I I II II

tll_ll

ISSUESiL II

CERTIFICATION REQUIREMENTS

OUT-OF-PLANE LOADING

ASSEMBLY INDUCED DELAMINATIONS

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I I

86

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p..-

iiiiii

NAVY STRUCTURALCERTIFICATION METHODOL OG Y

CAREFUL PLANNING AND COOROINATION BETWEEN THE NAVY AND THE CONTRACTOR ARE REQUIREDBEGINNING EARLY IN THE AIRCRAFT DEVELOPMENT PROGRAM.

THE DESIGN OEVELOPMENT TEST PROGRAM IS AN INTEGRAL PART OF THE CERTIfiCATION PROCESS.

STATIC STRENGTHS GREATER THAN DESIGN ULTIMATE LOAD ARE REQUIRED FOR THE OESIGN DEVELOP•

MENT TEST SPECIMENS TO ACCOUNT FOR:

- ENVIRONMENTAL STRENGTH DEGRADATION DUE TO TEMPERATURE AND MOISTURE.

- THE INCREASED SCATTER IN MATERIAL PROPERTIES DEMONSTRATED BY COMPOSITES (WHEN COM-

PARED TO METALS).

FULL SCALE TEST RESULTS MUST CORRELATE WITH DESIGN DEVELOPMENT TEST RESULT_

- MEASURED STRAINS IN CRITICAL AREAS MUST AGREF-

• FAILURE MODES MUST BE THE SAME.

• STATIC STRENGTH MUST ACCOUNT FOR SCAI"rER AND ENVIRONMENT,

ADEQUATE TIME AND RESOURCES MUST BE ALLOCATED FOR THE ENTIRE CERTIFICATION PROCESS.

SCHEDULE AND COST RESTRAINTS THAT LIMIT THE SCOPE OF THE DESIGN DEVELOPMENT PROGRAM

INCREASE THE RISK OF UNSUCCESSFUL FULL SCALE TESTS.

r

i:

(_ NAVY STRUCTURAL CERTIFICATIONMETHODOLOGY

I I I

JCOUPON

ELEMENT

FULL-SCALE TESTS

STATICFATIGUEFLIGHT

CERTIFICATION BEGINS EARLY IN DEVELOPMENT PROCESS

BUILDING BLOCK DEVELOPMENT APPROACH

CAREFULLY COORDINATED DEVELOPMENT PLANNING

ADEQUATE TIME AND RESOURCESI

87

_q

A V-8B COMPOSITE WING DEVELOPMENT-:

A. m,UP_ OFA. m_ m_Brr p.oom,u m 1t Avoncoupou_ w._-__IUOSllgq_ OF ADE_PATE 11MEAND FUNOING,THE NECESSARYAMOUNTOF ; - -.__ .... ___PtqoOUCllON TBTI_ WAS PERPC;UM_ PRIOR TO THE FABRICAllON OF THE FUI.I__Juncp._r. T.m _ pnoon_ mm_mm ooupo. TmrmmTOo_r,m mm_r-ou.ow_ uvJourr am acrep_au. _mTm. o.ce om._ _ wm!__

mms _o_cmn¢_ pmmo_ OF THS1_mus m:)xwmm ___,.o_4s _ movxm .mm_Y mrr OAT,_o u,U_UF_rUm_ _ A

TIMEFRAMEWHICHCANIMPACTTHEPINALOESIGN.

T.m nmm.,_ ,. _ _opm_ pnoonJaaPOnL_ _unmu_ _.oumm sc.mu Am) costa mAm_rs omm coumo.m T.m m.no_ __S.OUL:mSWU)STOr-o_ow_ ,uppno,c.TO_.s,ns ASUCCESSFULFULLSCALE_.

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1I_4lsTs _

m_s oes_ A_wbkss

Joints

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88

I

OUT-OF-PLANE ANAL YSES

OUT OF PLANE STRESSES ARE AN fliSUE IN COMPOSITES BECAUSE OF THEIR LOW INTERLAMINAR

STRENGTH. OUT OF PLANE 8TRESSES RESULT EITHER DIRECTLY FROM THE APPLICATION OF OUT-OF-

PLANE LOADS, 8UCH A8 FUEL PflESSURE, OR INDIRECTLY, UNDER IN PLANE LOADING, AS A RESULT OF

LAMINATE GEOMETRY SUCH AS LAMINATE CORNER RADII, PLY DROP-OFFE_ ETIFFENER RUN4)UT, AND

PANEL BUCKUNG DEFORMATION. WHILE THREE DIMENSIONAL fiNITE ELEMENT METHO08 CAN BE USED

TO ANALYZE THESE SITUATIONS, THEY REQUIRE TOO MUCH TIME FOR PREUMINAFIY STRUCTURAL SIZING.

IN A JOINT NAVYIFAA PROGRAM, THE PROBLEMS RESULTING FROM OUT-OF.PLANE LOA08 WERE INVESTI-

GATED AND WAYS WERE DEVELOPED FOR AVOIDING FAILURES THAT ARE C_USED BY THESE LOADS,

SIMPLE TWO DIMENSIONAL ANALYSIS METHOD6 WERE DEVELOPED TO PREDIC:r OUT.OF4I/.ANE FAILURE

STRENGTH OF COMPOSITE 8TRUCTURF._ ELEMENT TEST DATA WERE USED TO VERIFY THE ANALYSES.

THE METHODS AND EXPERIENCE FROM THIS PROGRAM WERE USED TO COMPILE A lILT OF DESIGN GUIDES

FOR DESIGNERS AND ANALYSTS.

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(_(_ POTENTIAL OUT-OF PLANE FAILURES

,,,., ...... ,.... ,..,."° ...... ,.p,.

........... _ in Ply Drop-OffJillInterlamlnar Tension / II

X Failure in Radius-Jt1/,...,,,__.,

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89

ASSEMBL Y INDUCED DELAMINA liONS

EARUER, I POINTED OUT A RECURRING PROBLEM IN MANUFACTURING, IN WHICH INTERPLY DELAMI-

NAlION8 OF WING SKINS AND :SUBSTRUCTURE OCCUR DURING ASSBiBLY. FREQUENTLY TItESE DE-

LAIINATION8 ARE A880CIATED WITH IMPROPER FASTENER INSTALLATION OR IMPROPER 81'WWING OF

MECHANICAL FASTENED JOINTS AS INDICATED ON Tltl8 VU-GRAPH. THESE DELAMINATION8 CAN;CAUSE

SIGNIFICANT REDUC'nON IN THE LOAD CARRYING CAPABILITY OF STRUCTURE, PARTICULARLY IN COM-

PRESBION 8TFIENGTH AND IN THE STRENGTH OF STRUCTURE SUBJECTED TO OUT-OF-PLANE LOADING. IN

AOOITION, THERE 18 A POTENTIAL FOR DELAMtNATION GROWTH UNDER FATIGUE LOADING, WHICH CAN

FURTHER REDUCE LOAD CARRYING CAPABILITY. CURRENTLY, ANALYTICAL METHODS TO .AINW.S8 THE

EFFECTS OF THESE DELAMINATIONS DO NOT EXIST. NADC AND THE FAA JOINTLY HAVE INITIATED A

PROGRAM TO:

(1) DEVELOP AND VALIDATE A METHODOLOGY FOR ASSESSING THE 8EVERrrY OF KNOWN OLq.AMINA-

WITH RESPECT TO THEIR EFFECT8 ON STRENGTH AND LIFE SO REPNR,'REPLACEMENT DECk

810N8 CAN BE MADE.

(2) PROVIDE DESIGN GUIDELINES FOR PREVENTION OF ASSEMBLY INDUCED OELAMINATIONS.

THIS WORK WILL BE REPORTED ON IN DETAIL DURING THIS CONFERENCE.

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ASSEMBL Y INDUCED DELAMINA lIONS............ 11 1 _iilI.................

8_(Jn

Un_lmm_l

"0" Ring Fmleners at SeatGroove

Variable Fastener Torque"

Countersink Radtue Too 8mall*

Fastener Mtsallgnment*

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90

FUTURE COMPOSITE USAGE RATIONALE

IN THE FUTURE THE DRIVER FOR THE SELECTION AND USAGE OF A COMPOSITE MATERIAL WILL NOT BESOLELY DEPENDENT UPON WEIGHT 8AVING_ OTHER MAJOR DRIVERS SUCH AS CO_I', MANUFACTURINGQUALITY, DAMAGE TOLERANCE, SURVNABIUTY, OBSERVABIUTY, SUPPORTABILITY, IN ADOITION TO RISKTO PROGRAM SCHEDULE AND AVAILABLE FUNDING MUST ALL BE TAKEN INTO CONSIDERATION. ONLYAPPLICATIONS WHERE THE PAYOFF IS SUFFICIENT TO JUSTIFY THE USE OF ADVANCED COMPOSITESSHOULD BE CONSIDEREO. ADDITIONALLY, TO INSURE THAT THESE PAYOFFS ARE REAUZED, BETTERMETHODS FOR PREDICTING WEIGHT AND COSTS IN A MANUFACTURING ENVIRONMENT MUST BE DEVEL-OPEO.

THE USE OF IMMATURE MATERIAL SYSTEMS MUST BE AVOIDED. PAST EXPERIENCE HAS 8HOWH THAT THECOMMITMENT TO A MATERIAL SYSTEM PRIOR TO ITS COMPLETE CHARACTERIZATION RESULTS IN PER-FORMANCE PENALTIES AND COSTLY PROGRAM DELAYS.

BUILDING A MILITARY AIRCRAFT REQUIRES SPECIALIZED EQUIPMENT AND EXPERIENCE RELATED TO COM-POSITE TECHNOLOGY. THE NAVY AND THE CONTFIACTOR MUST REAUZE THAT THIS CAPABILITY NEEDS TOEXIST AT THE START OF THE DEVELOPMENT PROGRAM AND CANNOT EXPECT IT TO BE ACQUIRED DURINGTHE PROGRAM.APPUCATIONS MUST TAKE ADVANTAGE OF THE AVAILABLE TECHNOLOGY BASE. SHOULD THE TECHNOL-OGY FOR A SPECIFIC APPLICATION NOT EXIST AT THE PROGRAM ON-SET, THE RISK OF FAILURE CAN BESIGNIFICANT.

FINALLY, IT MUST BE REALIZED THAT THE BEST MATERIAL FOR A PARTICULAR APPLICATION MAY NOT BEA COMPOSITE.

FUTURE COMPOSITES USAGE RATIONALEIIII I II

• ALL KEY DRIVERS - WEIGHT, COST, RISK, ETC.

• PAYOFF VS. APPLICATION

• PROGRAMMATICS - SCHEDULE, FUNDING, ETC.

• MATURITY OF MATERIAL SYSTEMS

• CONTRACTOR EXPERIENCE AND CAPABILITY

• OVERALL TECHNOLOGY BASE VS. APPLICATION

• BEST MATERIAL NOT ALWAYS COMPOSITES

91

FUTURE PERSPECTIVE

THE NAVY 18 COIBEITEO TO, ANO WlU. CONTINUE TO UM, ADVANCED COMFOelTEIi ON rill AIRCFIAFT._ _ I,ltFnll TOTHRNAW,_ WBaHT,I_F_ ANOCOlmOlOI¢Mmle-Tk4¢_ F_U_ounma_ _ LSm'A__o. THIn _--ARS NOt"oommcmm mlmv.

ARo _ul, Am vmJ._ TOram&wom_o THRoua_m _o mmm_T_ Tm_t_.oav WILLcommut TO_OLVE W_H commuma _ ONmmucma costa ARoIMPItOVING QUALITY THROUGH AUTOMATION. IN ALL OASF..8THE ¢_ ASJOCIATED WITH THE IJSE OF

MUST BE JUSTIFIED.

IN THE MATUIIAL8 8ELEC'I1ON AREA, TItERMOSETS WILL CONTINUE TO B| THE PRIMARY MATERIAL IN THEFOREGEEABLE FUTURE DUE TO THF.JFIMATURITY AND THE EXISTENCE OF AVAILABLE CAPITAL EQUIPMENT(AUTOCLAVU).THE 18SUES OF LOW OB$ERVABILITY AND SUPPORTABILITY WILL TAKE ON ADDITIONAL IMPORTANCE INTHE FUTUFIE.

][LII

I ....... r . J . I ..... I

• EVOLUTIONARY DEVELOPMENT OF TECHNOLOGY

• NAVY AIRCRAFT WILL CONTINUE TO USE COMPOMITd

• APPLICATIONS WILL HAVE TO JUSTIFY INCREASED COST

• QUANTUM ADVANCEMENT NEEDED IN MANUFACTURING

• MANUFACTURING QUALITY MUST BE IMPROVED

• THERMOSET8 CONTINUE TO BE THE PRIMARY MATERIAL IN THE FORESEEABLEFUTURE

• LOW OBSERVABIUTY WILL BE A DESIGN DRIVER

• SUPPORTABILITY WILL BE INCREASINGLY IMPORTANT

I

92

Advanced Materials Requirements and Needsfor Future Aerospace Applications

Samuel L Venneri

National Aeronautics and Space Adm/nistrationOffice of Aeronautics, Exploration and Technology

93

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94

SESSION H

AIRCRAFT DESIGN METHODOLOGY (A)

_ el.Al_. NOT Vll.mEO97

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